JP6111638B2 - Connecting rod breakage monitoring device and monitoring method thereof - Google Patents

Description

  The present invention relates to an apparatus for monitoring a breaking state when a connecting rod in which a small end and a large end are integrally formed is broken at the large end, and a monitoring method therefor.

  A connecting rod (connecting rod) that connects the crankshaft and piston of an engine has a large end connected to the crankshaft at one end of a shaft portion and a small end connected to the piston at the other end. Yes. A through hole into which a crank pin is fitted is provided at the large end, and a fitting hole into which a piston pin is fitted is provided at the small end. The through hole at the large end is composed of a semicircular portion provided in the shaft portion and a semicircular portion provided in a cap portion that can be attached to and detached from the shaft portion, and can be connected to the crankshaft. It has become.

In order to manufacture this connecting rod, the shaft part and the cap part may be molded separately. In recent years, however, the cracking method has been adopted in which the cap part is integrally formed of the material with the shaft part and the cap part is separated from the shaft part. Is adopted. The cracking method is a method of breaking a connecting rod into two at the through- hole portion by fitting a pair of half-shaped mandrels into the through- hole at the large end of the connecting rod and driving a wedge between the half-shaped mandrels. It is.

  In addition, V-shaped notches are provided on the left and right sides of the through-hole as breakage promoting portions, and a wedge member is driven to cause stress concentration in the V-shaped notch, thereby breaking the connecting rod. Thus, since it is a construction method which forcibly fractures the connecting rod at the large end, it is necessary to appropriately manage the fracture position and the properties of the fracture surface. Specifically, it is necessary to manage such that the left and right V-shaped notches are equally broken in the direction perpendicular to the shaft.

  As an invention for that, for example, in Patent Document 1, the breaking load and the breaking time generated when the connecting rod is broken are measured, and the measured breaking load and breaking time are compared with a predetermined value set in advance. By doing this, it is shown that the quality of the broken state of the connecting rod is judged.

JP 2005-74537 A

  However, in the invention of Patent Document 1, the quality of the breaking state of the connecting rod is judged based on the magnitude of the breaking load and the time during which the breaking load is applied. There was a possibility of being detected. That is, depending on the V-shaped notch shape, the fracture load may be higher than the predetermined value and the fracture time may be longer than the predetermined value, but the fracture may be determined to be defective.

  For example, when the radius of the tip roundness of the V-shaped notch is large, or when the notch angle is large, the stress concentration factor at the V-shaped notch portion is reduced, and the breaking load is increased. The breaking load also increases when the V-shaped notch depth is shallow. In this case, the breaking load increases from a predetermined value and the breaking time becomes longer than the predetermined value. As described above, depending on the shape of the V-shaped notch, it may be determined that the fracture is not good despite the normal fracture.

  Further, in the invention of Patent Document 1, since the rupture state is determined based on the rupture load and the rupture time, it cannot be determined whether there is a problem in the left or right rupture portion. Furthermore, the difference between the left and right fracture times is read from the change in load at the time of fracture, and the fracture state of the connecting rod is estimated.However, since the fracture time is very short, the fracture state of the connecting rod can be accurately determined from the difference between the right and left fracture times. It was difficult to judge.

  The present invention has been made in order to solve the above-described problems, that is, the breakage of the connecting rod capable of accurately detecting failure due to the cracking method regardless of the shape of the breakage promoting portion such as a V-shaped notch. An object is to obtain a monitoring apparatus and a monitoring method thereof.

  In order to solve the above problems, the present invention is configured as follows.

In the first aspect of the present invention, a pair of halved mandrels is fitted into a through hole on the large end side of a connecting rod in which a large end and a small end are integrally formed, and the pair when broken at breaking portions of the left and right from the fracture facilitating portion provided on the right and left sides in advance the through-hole of the large end of the connecting rod by going by implanting wedges in the shaft-side and the cap portion between the mandrel A connecting rod breakage monitoring device for monitoring a breakage state, comprising a pair of left and right strain detection means provided on a holding means for holding the cap side on both the left and right sides at the time of breakage, and a pair of left and right strain detection means at the time of breakage Rupture determining means for determining a rupture state based on detection signals output respectively, and the rupture determining means is based on a difference between left and right strains detected by the pair of left and right strain detecting means. the left and right of the connecting rod And judging the quality of the cut-away of the tear portion.

According to a second aspect of the present invention, in the first aspect of the invention, the strain detecting means is provided in a pair on the left and right sides of the holding means and at least one of the pair of mandrels, respectively. It is characterized by.

The invention according to claim 3 is the invention according to claim 1 or 2 , wherein the breakage promoting portion is a V-shaped notch for breakage, and the breakage determining means uses the V-shaped breakage for breakage. A warning means is provided for warning when the machining state of the notch is determined to be defective.

According to a fourth aspect of the present invention, in the invention according to the third aspect , the break determination means has a difference between right and left strains detected by the pair of left and right strain detection means n times or more (n is It is characterized in that it is determined that the breaking V-shaped notch is defective in shape when it is continuously greater than a predetermined value.

According to a fifth aspect of the present invention, in the invention of the fourth aspect , the automatic tool changing mechanism is provided when the fracture determining means determines that the V-shaped notch for fracture is defective in shape. The V-shaped notch machining apparatus is provided with an instruction means for instructing automatic tool change.

According to a sixth aspect of the present invention, a pair of halved mandrels is fitted into a through- hole on the large end side of a connecting rod in which a large end and a small end are integrally formed, and the pair of mandrels Break when the big end of the connecting rod is broken in the left and right breaks from the breakage promotion part provided in advance on the left and right sides of the through hole to the shaft part and the cap part by driving a wedge in between A method for monitoring a state, wherein a first step of detecting strain generated at the time of breakage by a pair of left and right strain detection means provided on a holding means for holding the cap portion side on both right and left sides at the time of breakage, A second step of determining a fracture state based on detection signals respectively output from the pair of left and right strain detection means, and in the second step, depending on the difference in strain detected by the pair of left and right strain detection means The computer And judging the quality of the cut-away of the left and right breaking parts of the head.

The invention according to claim 7 is the invention according to claim 6 , wherein the pair of left and right strain detecting means in the first step is a pair of left and right strains provided in at least one of the pair of mandrels, respectively. It includes a detection means.

The invention according to claim 8 is the invention according to claim 6 or 7, wherein the breakage promoting portion is a V-shaped notch for breaking, and in the second step, the V-shaped for breaking. The method further includes a step of warning when the processing state of the notch is determined to be defective.

The invention according to claim 9 is the invention according to claim 8, wherein in the second step, the difference between the left and right strains output from the pair of left and right strain detection means is n times or more (n Is an integer greater than or equal to 1), and further has a step of determining that the V-shaped notch provided in the connecting rod is defective in shape when continuously larger than a predetermined value.

The invention according to claim 10 includes an automatic tool change mechanism in the invention according to claim 9, when it is determined in the second step that the V-shaped notch has a defective shape. The method further includes the step of instructing the V-shaped notch processing device to perform automatic tool change.

  According to the first aspect of the present invention, since the strain detecting means is provided in a pair of left and right holding means for holding the cap, whether or not the broken state of the connecting rod is good or not based on the detection signals respectively output from the strain detecting means. Can be determined. That is, it is possible to reduce the possibility of erroneously determining the breaking state of the connecting rod based on the magnitude of the breaking load and / or the additional time of the breaking load, and to accurately determine whether the connecting rod is broken or not.

  In addition, since the strain detecting means is provided in a pair on the left and right, the rupture states of the left and right rupture portions can be accurately determined based on the detection signals output from the strain detection means.

Further , the quality of the broken state of the connecting rod can be determined based on the difference between the left and right strains respectively output from the strain detecting means. That is, it is possible to accurately determine whether the connecting rod is broken or not.

In addition, according to the second aspect of the present invention, since a plurality of pairs of left and right strain detecting means are provided, it is possible to more accurately determine whether the connecting rod is broken or not.

Further, according to the invention described in claim 3 , by providing the breakage failure warning means, it is possible to prompt the operator to confirm the breakage state. Thereby, confirmation of the broken state of the connecting rod can be determined with higher accuracy.

According to the fourth aspect of the present invention, when the difference between the left and right strains detected by the pair of left and right strain detecting means is continuously greater than a predetermined value for a predetermined number of times or more, the V-shape as the breakage promoting portion. It is determined that the shape of the shape notch is defective. Here, it is considered that the failure of the breakage of the connecting rod occurs continuously because the processing state of the V-shaped notch provided in the connecting rod is defective. In other words, when failure of the connecting rod occurs continuously, the cause of the failure is identified early as a V-shaped notch processing failure, thereby reducing the incidence of defective connecting rod products it can.

According to the fifth aspect of the present invention, the difference between the left and right strains detected by the pair of left and right strain detection means is continuously larger than a predetermined value for a predetermined number of times or more, and the V-shaped notch is detected by the break determination means. When the machining state is determined to be defective, the V-shaped notch machining apparatus having an automatic tool change function automatically replaces the worn tool.

  Thereby, the shape defect of the V-shaped notch as the breakage promoting portion can be eliminated at an early stage, and the occurrence rate of defective breakage of the connecting rod can be reduced. In addition, the tool can be used to the end of its life by monitoring the broken state of the connecting rod without having to monitor the wear state of the V-shaped notch cutting tool. Thereby, the cost of the tool can be reduced.

According to the sixth aspect of the present invention, the break determination means is connected to the connecting rod based on the detection signals output from the pair of left and right strain detection means provided in the holding means for holding the cap portion side at the time of breakage. Judge the quality of the broken state. Therefore, it is possible to reduce the possibility of erroneous determination of the breaking state of the connecting rod based on the magnitude of the breaking load and / or the addition time of the breaking load, and to accurately determine whether the connecting rod is broken or not.

Further , the quality of the broken state of the connecting rod can be determined based on the difference between the left and right strains respectively output from the strain detecting means. That is, it is possible to accurately determine whether the connecting rod is broken or not.

According to the seventh aspect of the present invention, since a plurality of pairs of left and right strain detecting means are provided, it is possible to more accurately determine whether the connecting rod is broken or not.

According to the eighth aspect of the present invention, when the difference between the left and right strains detected by the pair of left and right strain detecting means is continuously greater than a predetermined value for a predetermined number of times or more, the V-shape as the breakage promoting portion. It is determined that the shape of the shape notch is defective. In other words, when failure of the connecting rod occurs continuously, the cause of the failure is identified early as a V-shaped notch processing failure, thereby reducing the incidence of defective connecting rod products it can.

According to the ninth aspect of the present invention, the difference between the left and right strains detected by the pair of left and right strain detection means is continuously greater than a predetermined value for a predetermined number of times or more, and the V-shaped notch is detected by the break determination means. When it is determined that the machining state is defective, a warning is given that the machining state of the V-shaped notch is determined to be defective. This prompts the operator to confirm the processing state of the V-shaped notch, identifies the cause of the continuous failure of the connecting rod, and reduces the occurrence rate of defective connecting rod products.

According to the tenth aspect of the present invention, the difference between the left and right strains detected by the pair of left and right strain detection means is continuously greater than a predetermined value for a predetermined number of times or more, and the V-shaped notch is detected by the break determination means. When the machining state is determined to be defective, the V-shaped notch machining apparatus having an automatic tool change function automatically replaces the worn tool.

  As a result, the shape defect of the V-shaped notch can be eliminated at an early stage, and the occurrence rate of defective breakage of the connecting rod can be reduced. In addition, the tool can be used to the end of its life by monitoring the broken state of the connecting rod without having to monitor the wear state of the V-shaped notch cutting tool. Thereby, the cost of the tool can be reduced.

It is a figure which shows the connecting rod. 1 is a diagram schematically showing a configuration of a connecting rod breaking processing system 1. 1 is a diagram schematically showing a configuration of a connecting rod breakage monitoring device 10. FIG. It is a figure which shows roughly the structure of the fracture process part of the connecting rod fracture | rupture monitoring apparatus. It is a figure which shows roughly the structure of the V-shaped notch processing apparatus. It is an enlarged view which shows one example of notch N1, N2. It is a figure which shows the change of the distortion of a cap holding part at the time of a fracture | rupture of the connecting rod provided with the notch of FIG. It is a figure which shows the change of the distortion of the mandrel 12 in the same case as FIG. It is a figure which shows the torn surface at the time of the fracture | rupture of the connecting rod provided with the notch of FIG. It is an enlarged view showing other examples of notches N1 and N2. It is a figure which shows the change of the distortion of a cap holding part at the time of a fracture | rupture of the connecting rod provided with the notch of FIG. It is a figure which shows the change of the distortion of the mandrel 12 in the same case as FIG. It is a figure which shows the torn surface at the time of a fracture | rupture of the connecting rod provided with the notch of FIG. It is a flowchart which shows the processing content of the connecting rod fracture | rupture monitoring apparatus.

  First, the connecting rod according to the present invention will be described. FIG. 1 is a view showing a connecting rod, FIG. 1a is a plan view, and FIG. 1b is a cross-sectional view of the connecting rod taken along line AA in FIG. 1a.

  The connecting rod shown by the symbol W in FIG. 1 is formed of a steel material and includes a through hole small diameter hole H1 that supports the piston pin and a through hole large diameter hole H2 that supports the crank pin. Strictly speaking, the rod W1 and the cap It consists of two parts with W2. A tightening seat surface S for a bolt that joins the rod W1 and the cap W2 is provided on the cap W2 in a pair of left and right.

  The manufacturing method of the connecting rod W will be described. The connecting rod W is not manufactured from two parts of the rod W1 and the cap W2 from the beginning, but is manufactured by integrating them. Next, the small-diameter hole H1 and the large-diameter hole H2 are each processed to have a predetermined roundness (for example, polishing), and then the fracture line BL (passes through the center of the large-diameter hole H2, The large-diameter hole H2 is broken in a direction perpendicular to the parallel direction B of the large-diameter hole H2 to form two parts, a rod W1 and a cap W2.

  Therefore, the rod W1 and the cap W2 are provided with the same roundness semicircular bearing surface for receiving the crankpin (the inner peripheral surface P of the large-diameter hole H2 before breaking).

  Further, the connecting rod W is provided with V-shaped cutouts (notches) N1 and N2 as breakage promoting portions so as to break along the break line BL. The notches N1 and N2 are formed along the axial direction of the inner peripheral surface P on the breaking line BL of the large-diameter hole H2, and are produced by broaching, for example. When the stress concentration occurs in the notches N1 and N2, the connecting rod W is broken at the breaking line BL.

  The notches N1 and N2 have a notch depth D in the radial direction of the large-diameter hole H2, a notch angle θ, and a notch tip roundness R. The direction parallel to the BL direction is the left-right direction, the notch N1 is provided in the right-side broken portion, and the notch N2 is provided in the left-side broken portion.

  Hereinafter, the connecting rod breaking processing system 1 for breaking the connecting rod W into the rod W1 and the cap W2 will be described. FIG. 2 is a diagram schematically showing the configuration of the connecting rod fracture processing system 1. As shown in FIG. 2, the connecting rod breakage processing system 1 includes a connecting rod breakage monitoring device 10 and a plurality of V-shaped notch processing devices 30 (# 1 to # 6). The connecting rod breakage monitoring device 10 is connected to each V-shaped notch processing device 30 via an in-factory Ethernet 50, and is configured to be able to communicate with each other. Each connecting rod W is first processed into a V-shaped notch in the V-shaped notch processing device 30, and thereafter connected rod breakage monitoring is performed together with information on the device 30 that processed the V-shaped notch (for example, 30 # 1). It is conveyed to the apparatus 10.

  Next, the configuration of the connecting rod breakage monitoring device 10 will be described below with reference to FIG. FIG. 3 is a diagram schematically showing the configuration of the connecting rod breakage monitoring device 10. As shown in FIG. 3, the connecting rod breakage monitoring device 10 includes a pair of half-shaped mandrels 12 and 14 fitted into the large-diameter hole H2 of the connecting rod W, and a wedge 16 driven between the mandrels 12 and 14. An actuator 18 for moving the wedge 16, a rod holding portion 20 and a cap holding portion 22 for holding the connecting rod W against the pair of mandrels, and a cap holding portion 22 and a pair of mandrels 12 when the connecting rod W is broken. , 14, a strain gauge 24 for detecting strain generated, a breakage failure warning unit 26 for warning when the broken state of the connecting rod W is bad, and determining whether the broken state of the connecting rod W is good or not, and controlling the connecting rod breakage monitoring device 10. And a control device 28.

  The pair of mandrels 12 and 14 is configured to be fitted into the large-diameter hole H2 of the connecting rod W, and a pressing surface 12a for contacting and pressing the inner peripheral surface P of the large-diameter hole H2 of the connecting rod W. 14a and tapered surfaces 12b and 14b that come into contact with the wedge 16 are provided. In the present embodiment, the mandrel 12 is located on the cap side, and the mandrel 14 is located on the rod side. Although not shown, the pair of mandrels 12 and 14 are restricted so as to move only in the parallel direction B of the small diameter hole H1 and the large diameter hole H2 of the connecting rod W (for example, the mandrels 12 and 14 are And configured to move on rails extending in the parallel direction B.).

  The wedge 16 is configured to move between the pair of mandrels 12 and 14 in the axial direction of the large-diameter hole H2 of the connecting rod W, and presses the tapered surfaces 12b and 14b of the mandrels 12 and 14, 14 are moved in the parallel direction B so as to be separated from each other.

  The actuator 18 is for pressing and moving the wedge 16 in the axial direction of the large-diameter hole H2 of the connecting rod W.

  Hereinafter, with reference to FIG. 4, the attachment position of the rod holding part 20, the cap holding part 22, and the strain gauge 24 will be described in detail. FIG. 4 is a diagram schematically showing the configuration of the breaking portion of the connecting rod breakage monitoring device 10.

  As shown in FIG. 4, the rod holding portion 20 is configured to hold the small end portion of the rod W <b> 1 facing the mandrel 14, and has a substantially V-shaped form. The rod holding portion 20 is coupled to the mandrel 14 and moves while holding the rod W1 as the mandrel 14 moves.

  The cap holding part 22 is configured to hold the cap W2 side against the mandrel 12 on both the left and right sides, and has a pressing surface 22a for contacting and pressing the seating surface S of the cap W2.

  The strain gauges 24 a and 24 b are for detecting strain generated in the cap holding part 22, and are attached to the side surfaces 22 b on both sides of the cap holding part 22 so as to form a pair. The strain gauges 24c and 24d are attached to the mandrel 12 on the cap side, and the strain gauges 24e and 24f are attached to the mandrel 14 on the rod side, and are attached to form a pair of left and right. The strain gauges 24c to 24f attached to the mandrel are attached to the left and right ends of the mandrel pressing surfaces 12a and 14a, respectively.

  A voltage is applied to each of the strain gauges 24a to 24f, and the strain is detected from a change in the voltage. As described above, the strain gauges 24a to 24f are attached to form a pair of left and right, respectively, so that strain generated in a member to which a load is applied at the time of breaking can be detected on both the left and right sides.

  When the controller 28 determines that the connecting rod is broken, the breaking failure warning unit 26 warns the worker that the connecting rod is broken and confirms the broken state to the operator. Prompt. This warning may include information as to which of the left and right fracture portions is determined to be a fracture failure and information about the V-shaped notch processing device 30 that has processed the V-shaped notch of the connecting rod W.

  The control device 28 includes a maximum strain detection unit 282 that detects the maximum value of strain detected by the strain gauges 24 a to 24 f, a break determination unit 284 that determines the breaking state of the connecting rod, and the V-shaped notch processing device 30. A tool change instruction transmission unit 286 for instructing tool change.

  The maximum strain detector 282 is for detecting the maximum value of the strain detected by the strain gauges 24a to 24f, and from each strain change detected by the strain gauges 24a to 24f, for each strain gauge 24a to 24f. The maximum strain per cycle of the breaking process is detected.

  The fracture determination unit 284 is for determining the fracture state of the connecting rod. From each maximum strain detected by the maximum strain detector 282, the absolute value of the difference between the left and right maximum strains is calculated for each member with a strain gauge attached to the left and right pair, and the difference is preset for each member. When the threshold values are larger than the threshold values X, Y, Z, it is determined that the fracture state is defective. When it is determined that the fracture is defective, the connecting rod fracture monitoring device 10 is stopped and the fracture failure warning unit 26 is activated. The threshold values X, Y, and Z are threshold values set in advance for the cap holding unit 22 and the mandrels 12 and 14, respectively.

  In addition, the break determination unit 284 determines which of the left and right broken parts is a broken defect from the pair of left and right maximum strains. Specifically, it is determined that the pair of left and right rupture portions in the direction with the highest maximum strain breaks first, the rupture portion in the direction with the lower maximum strain ruptures later, and the rupture portion in the direction in which the rupture later breaks is defective. Is determined.

  When the connecting rod breakage monitoring device 10 is restarted after confirmation of the breakage state by the operator, the breakage determination unit 284 again determines that the breakage is defective, and it is determined that the breakage failure continues for n times or more (n is an integer of 1 or more). If it is determined that there is, the tool change instruction transmission unit 286 is activated. It should be noted that the tool change instruction transmission unit 286 may be activated when breakage failures continue in a specific left-right direction, or the breakage failure continues not only because a breakage failure has occurred in a specific direction. In some cases, the tool change instruction transmission unit 286 may be activated.

  The tool change instruction transmitting unit 286 is for transmitting a tool change instruction to the V-shaped notch processing device 30, and the tool is sent to the V-shaped notch processing device 30 according to the determination result according to the breaking state of the break determining unit 284. Send exchange instructions. In other words, when it is determined that there is a fracture failure continuously n times or more, the shape of the V-shaped notch is presumed to be the cause of the failure of the fracture, so that the cutting edge wears out the tool that forms the V-shaped notch. By replacing it with one that has not been done, the failure to break can be resolved at an early stage. Note that the tool change instruction includes information indicating which of the left and right fracture portions is determined to be a fracture failure. The tool change instruction is transmitted to the device 30 that has processed the V-shaped notch of the connecting rod.

  Next, the configuration of the V-shaped notch processing device 30 will be described below with reference to FIG. FIG. 5 is a diagram schematically showing the configuration of the V-shaped notch processing device 30. As shown in FIG. 5, the V-shaped notch processing device 30 includes a tool 32 for processing a V-shaped notch, a connecting rod holding portion 34, an automatic tool changer 36, and a V-shaped notch processing device. A known machining center including a control device 38 for controlling the operation.

  In the present embodiment, a V-shaped notch is formed by broaching. That is, the tool 32 is a broaching tool, and has a plurality of replaceable cutting edges 32a. When the cutting edge 32a is worn, the cutting edge is not worn (new or re-polished). It is comprised so that it can replace | exchange for the cutting blade 32a. Note that the tool 32 according to the present embodiment includes two sets of left and right cutting blade sets 32a1 and 32a2, and the pair of left and right notches N1 and N2 are processed by the respective cutting blade sets 32a1 and 32a2. It is configured.

  The connecting rod holding part 34 is for holding the connecting rod W.

  The automatic tool changer 36 is for automatically changing a tool attached to the machining axis of the V-shaped notch machining device 30 to a spare tool 32 'accommodated in advance, and is a known and generally provided in a machining center. Device.

  The control device 38 includes a tool change instruction receiving unit 382 and a tool change instruction unit 384. The tool change instruction receiving unit 382 receives the tool change instruction transmitted from the connecting rod breakage monitoring device 10 and activates the tool change instruction unit 384. The tool change instruction unit 384 instructs the automatic tool changer 36 to change the tool.

  According to such a connecting rod breakage processing system 1, first, as shown in FIGS. 3 and 4, the connecting rod W is attached to the connecting rod breakage monitoring device 10 by the rod holding portion 20 and the cap holding portion 22, and the large-diameter hole H2 is formed. A pair of mandrels 12 and 14 are fitted. Next, the wedge 18 is moved between the mandrels 12 and 14 by the actuator 18. The wedge 16 presses against the mandrels 12 and 14 and starts to press the mandrels 12 and 14 in the parallel direction B.

  The force of pushing the wedge 16 of the actuator 18 is gradually increased, whereby the mandrels 12 and 14 expand the large-diameter hole H2 of the connecting rod W in the parallel direction B. At this time, the strain gauges 24 a to 24 f detect strain generated in the cap holding portion 22 and the pair of mandrels 12 and 14. That is, a compressive stress or a tensile stress acts on the cap holding portion 22 and the pair of mandrels 12 and 14 to cause distortion.

  Further, when the force pushing the wedge 16 of the actuator 18 is increased, the large-diameter hole H2 of the connecting rod W is further expanded by the mandrels 12 and 14, and the connecting rod W is broken at the breaking line BL starting from the notches N1 and N2.

  At this time, the mode of fracture differs depending on the shape of the notches N1 and N2. Specifically, when the notch tip roundness R is small or the notch angle θ is small, the stress concentration coefficient increases, so that stress concentration on the notch is promoted and breakage occurs early. On the contrary, when the notch tip R is large or the notch angle θ is large, the stress concentration coefficient is low, so that stress concentration on the notch is not promoted and does not break early.

  Similarly, as the notch depth D in the radial direction is deeper, the width of the fracture portion becomes shorter, so that the stress generated at the notches N1 and N2 becomes higher and breakage occurs earlier. On the contrary, since the width | variety of a fracture | rupture part becomes long when the notch depth D to radial direction is shallow, the generated stress to this notch becomes low and it does not fracture early. That is, when the shapes of the notches N1 and N2 are different, since the stresses generated at the left and right broken portions are different, the left and right broken portions do not break at substantially the same time.

  With reference to FIGS. 6 to 9, the case where the left and right fracture portions break at substantially the same time, that is, the case where both fracture straightly in the BL direction will be described. FIG. 6 is a diagram showing a case where the shapes of the notches N1 and N2 are substantially the same, and FIGS. 7 and 8 show changes in strain detected by the strain gauges 24a to 24d attached to the cap holding part 22 and the cap side mandrel 12, respectively. FIG. 9 is a diagram showing a fracture surface of the connecting rod W after fracture.

  As shown in FIG. 6, the notches N <b> 1 and N <b> 2 have the same notch tip roundness R, a notch angle θ, and a notch depth D. In this case, since the stress concentrations in the notches N1 and N2 are substantially the same, as shown in FIGS. 7 and 8, the strain changes detected by the strain gauges 24a to 24d are substantially equal. The broken portion on the side and the broken portion on the notch N2 side are broken at substantially the same time.

  At this time, each maximum strain is detected by the maximum strain detector 282, and the difference between the left and right of the maximum strain is calculated for each member by the break determination unit 284. Specifically, the left and right differences S1 and S2 of the maximum strain calculated as shown in FIGS. 7 and 8 are lower than the preset threshold values X and Y, so the break determination unit 284 determines that the break state is good. judge. In this case, as shown in FIG. 9, both broken portions can be broken almost straight and a good fracture surface can be obtained.

  Next, with reference to FIGS. 10 to 13, the case where the left and right fracture portions break at different timings, that is, one fracture portion does not break straight in the BL direction will be described. FIG. 10 is a view showing an example of a V-shaped notch when the shapes of the notches N1 and N2 are different. FIGS. 11 and 12 show strain gauges 24a to 24d attached to the cap holding part 22 and the cap side mandrel 12, respectively. FIG. 13 is a diagram showing a fracture surface of the connecting rod W after fracture.

  As shown in FIG. 11, the notches N1 and N2 differ only in the notch tip roundness R, and the notch angle θ and the notch depth D are the same. The notch N2 has a notch tip roundness R smaller than the notch N1. In this case, since the stress concentration on the notch N2 is larger than that of the notch N1, the fracture on the notch N2 side shown on the left side is broken first, and the fracture on the notch N1 side shown on the right side is delayed. become.

  As shown in FIG. 11, the maximum strain value 24b1 detected by the strain gauge 24b attached to the notch N2 side is larger than the maximum strain value 24a1 detected by the strain gauge 24a attached to the notch N1 side. This means that the left rupture portion side including the notch N2 side having a large stress concentration extends from the rupture portion on the right side, and as a result, presses the left side of the cap holding portion 22 through the cap W2.

  Also, as shown in FIG. 12, the maximum strain value 24c1 detected by the strain gauge 24c attached to the right fracture portion is larger than the maximum strain value 24d1 detected by the left strain gauge 24d. This means that the left rupture portion side including the notch N2 side having a large stress concentration extends from the right rupture portion, and as a result, the force with which the left side of the mandrel 12 presses the inner peripheral surface P of the connecting rod W is weakened. To do. In the combination of the notches N1 and N2 having such a shape, as shown in FIG. 13, the right-side fracture portion including the notch N1 side that fractures late is not straight.

  That is, when the shapes of the notches N1 and N2 are substantially the same, both fractured portions are fractured substantially simultaneously, and a substantially straight fracture surface can be obtained. On the other hand, when there is a difference in the shapes of the notches N1 and N2, and there is a difference in the stress generated in the two fracture portions, the one with the higher stress will break first, and the other will break. As a result, the fracture surface of the other fractured part that has been fractured late is not straight.

  The processing contents for determining the breaking state of the connecting rod by the control device 28 at this time will be described below with reference to the flowchart of FIG. First, the maximum strain is detected from the change in strain detected by each strain gauge 24 by the maximum strain detector 282 (step S101). Subsequently, the break determination unit 284 calculates the difference between the left and right maximum values for each member (step S102).

  Specifically, as shown in FIG. 11, the maximum value of the strain change detected by the strain gauge 24a attached to the cap holding part 22 is 24a1, and the maximum value of the strain change detected by the strain gauge 24b is 24b1. Next, the break determination unit 284 calculates a difference S1 between 24a1 and 24b1, and compares the difference with a preset threshold value X.

  In this case, since the difference S1 is larger than the threshold value X, the fracture determination unit 284 determines that the fracture state is defective (step S103). Such processing by the breakage determination unit 284 is performed for each member to which the strain gauges are attached to the left and right pairs.

  Furthermore, the break determination unit 284 determines which one of the left and right break portions has a break failure, and activates the break failure warning unit 26. (Step S104). Specifically, the absolute values of the left and right maximum strains for each member are compared. In order to determine a defective fracture portion from the strain gauge attached to the cap holding portion 22, it is determined that the side having the largest absolute value of the maximum strain, that is, the left fracture portion including the strain gauge 24b has been fractured first, and the right fracture portion Is determined to be defective.

  On the other hand, in order to determine a fracture failure portion from the strain gauge attached to the mandrel 12, it is determined that the fracture portion on the side having the smaller absolute value of the maximum strain, that is, the left fracture portion including the strain gauge 24d has been fractured first. Is determined to be defective. That is, when determining the rupture site from the strain gauge attached to the cap holding portion 22, it is determined that the rupture portion on the side where the absolute value of the maximum strain is low ruptured later, and conversely, the strain gauge attached to the mandrels 12 and 14 When determining the fracture site from the above, it is determined that the fracture portion on the side where the absolute value of the maximum strain is higher fractured later.

  The breakage failure warning unit 26 stops the connecting rod breakage monitoring device 10, and informs the operator that the worker has determined that the breakage state is unsatisfactory, along with information on the left and right positions of the breakage portion determined to be breakage failure. Notification is made (step S105). As a result, the operator can confirm the actual broken rod W by referring to the information on the part where the broken state of the connecting rod is determined to be defective.

  Even after the connecting rod breakage monitoring device 10 is restarted, the breakage determination unit 284 continuously determines that the breakage state of the breakage part in a specific direction in either the left or right direction is not less than n times (n is an integer of 1 or more). If it is determined, the tool change instruction transmission unit 286 is activated (step S106).

  The tool change instruction transmission unit 286 transmits a tool change instruction to the V-shaped notch machining apparatus 30 via the factory Ethernet 50 (step S107).

  When the V-shaped notch machining facility 30 receives the tool change instruction by the tool change instruction receiving unit 382, the tool change instruction unit 384 is activated (step S301), and the tool change instruction unit 384 exchanges the tool with the automatic tool changer 36. An instruction is given (step S302).

  That is, when it is determined that a fracture portion in a specific direction is defective continuously for n times or more, it is estimated that there is a difference in shape between the notches N1 and N2, and thus the notches N1 and N2 are formed. By exchanging the tool 32, the shape difference between the notches N1 and N2 can be eliminated. As a result, it is possible to eliminate breakage failure due to the shape difference between the notches N1 and N2.

  Thereafter, the cutting blade 32a of the tool 32 removed from the V-shaped notch processing device 30 is completely replaced with the tip 32a whose blade edge is not worn, and is stored in the tool storage portion of the automatic tool changing device 36, Prepare for the next tool change instruction.

  In addition, since the tool replacement instruction includes information on which of the left and right fracture portions is determined to be defective, which cutting blade set 32a1, 32a2 of the tool 32 has a problem, That is, it is possible to estimate whether the wear has occurred. For this reason, only the cutting blade set in which the problem is estimated can be replaced with a chip set in which the cutting edge is not worn.

  However, when only one of the cutting blade sets 32a1 and 32a2 is replaced with a cutting blade 32a whose blade edge is not worn, the wear state of the pair of left and right cutting blades 32a1 and 32a2 is different, and the notches N1 and N2 There will be a difference in shape. As a result, the difference in the generated stress at both fractured portions due to the difference in shape between the pair of left and right notches N1 and N2 becomes large, which tends to result in failure. For this reason, it is desirable to replace all the left and right pair of chip sets 32a1 and 32a2 at the same time. Furthermore, by exchanging at the same time, the frequency of exchanging the tools can be reduced, and the work efficiency of exchanging the tools 32 can be improved.

  As a result, the shape defect of the V-shaped notch can be eliminated at an early stage, and the occurrence rate of defective breakage of the connecting rod can be reduced. Further, the life of the tool 32 can be used to the limit by monitoring the breaking state of the connecting rod W without having to monitor the wear state of the V-shaped notch cutting tool 32. Thereby, the cost of the tool 32 can be reduced.

  However, a tool change instruction may be transmitted immediately after the tool 32 is changed. In this case, it is considered that only a specific cutting edge 32a has a defect such as a defect, and only the cutting edge 32a may be replaced with a cutting edge 32a in which the cutting edge is not worn. Thereby, the cost of the cutting blade 32a can be reduced as compared with the case where all the cutting blades are replaced.

  Further, when no problem such as a chipping is found in the specific chip 32a, it is considered that a problem has occurred in the positional relationship between the connecting rod holding portion 32 and the tool 34 of the V-shaped notch processing device 30. In such a case, it is desirable for the operator to confirm the positional relationship between the connecting rod holder 34 and the tool 34.

  As described above, according to the present embodiment, the strain gauges 24a to 24f for detecting the strain generated when the connecting rod W is broken and separated are provided on the cap holding portion 22 and the pair of mandrels 12 and 14, respectively. By calculating the absolute value of the left-right difference of the detected maximum strain for each member and comparing with the preset threshold values X, Y, Z, the quality of the fractured state of the fractured portion of the connecting rod W is accurately determined. it can.

  That is, it is not necessary to determine the breaking state of the connecting rod W based on the magnitude of the breaking load and / or the additional time of the breaking load, and the quality of the breaking state of the breaking portion of the connecting rod W can be accurately determined. As a result, it is possible to reliably prevent the defective product of the connecting rod W from flowing out.

  In addition, when the difference between the left and right of the maximum strain for each member is greater than the threshold value continuously for a predetermined number of times or more, it is determined that the processing state of the V-shaped notch for fracture is defective. If it occurs, the cause of the breakage failure is identified early as a V-shaped notch machining failure, and the tool 32 of the V-shaped notch machining device 30 is replaced with a tool 32 ′ whose blade edge is not worn. it can. As a result, it is possible to reduce the incidence of defective connecting rods.

  In the above-described embodiment, notches N1 and N2 having V-shaped notches are formed as breakage promoting portions for promoting breakage on the inner peripheral portion of the through hole of the connecting rod W. In addition, a breakage promoting portion may be provided on the outer peripheral portion of the connecting rod W. Further, instead of forming the notches N1 and N2 by broaching, notch N1 and N2 may be formed by forming a notch along the breaking line of the inner peripheral portion of the through-hole of the connecting rod W by laser processing. That is, the shape and processing method of the breakage promoting portion are not limited to the above-described embodiment.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made without departing from the spirit and scope of the present invention described in the claims.

  As described above, according to the connecting rod breaking device and the monitoring method provided with the breaking monitoring means according to the present invention, it is possible to accurately determine the breaking state of the connecting rod. Needless to say, the present invention can be applied not only to the connecting rod but also to an apparatus that breaks and separates other metal parts at the penetrating portion. Therefore, the present invention may be suitably used in an industrial field that uses an apparatus that breaks and separates a metal part at a penetrating portion.

DESCRIPTION OF SYMBOLS 1 Connecting rod breaking processing system 10 Connecting rod breaking device 12 Rod side mandrel 14 Cap side mandrel 16 Wedge 18 Actuator 20 Rod holding part 22 Cap holding part 24 Strain gauge 26 Breaking failure warning part 28 Control device 282 Maximum strain detection part 284 Breaking judgment part 286 Tool change instruction transmission unit 30 V-shaped notch processing device W Connecting rod W1 Rod W2 Cap N1, N2 Notch BL Break line

Claims (10)

The connecting rod is formed by fitting a pair of halved mandrels into a through- hole on the large end side of a connecting rod in which a large end and a small end are integrally formed, and driving a wedge between the pair of mandrels. A breakage monitoring device for a connecting rod for monitoring a breakage state when the left and right breakage parts are broken from the breakage promoting part provided in advance on the left and right sides of the through hole to the shaft part side and the cap part side. ,
A pair of left and right strain detection means provided in a holding means for holding the cap part side on both the left and right sides when breaking;
Rupture determination means for determining a rupture state based on detection signals respectively output from the pair of left and right strain detection means at the time of rupture,
The rupture determining means determines whether the rupture state of the left and right rupture portions of the connecting rod is good or not based on a difference between right and left strains detected by the pair of left and right strain detecting means. Monitoring device. The strain detection means is provided in a pair of left and right on the holding means and at least one of the pair of mandrels,
The connecting rod breakage monitoring device according to claim 1. The breakage promoting portion is a V-shaped cutout for breakage,
A warning means for warning when the breakage determination means determines that the processing state of the breaking V-shaped notch is defective;
The connecting rod breakage monitoring device according to claim 1 or 2. The rupture determining means is configured to generate the V-shaped rupture when the difference between the left and right strains detected by the pair of left and right strain detecting means is greater than a predetermined value continuously n times or more (n is an integer of 1 or more). It is determined that the shape notch is defective in shape,
4. A connecting rod breakage monitoring device according to claim 3. Instructing means for instructing automatic tool change to a V-shaped notch processing device provided with an automatic tool changing mechanism when the break determining means determines that the V-shaped notch for breaking has a defective shape. With
The connecting rod breakage monitoring device according to claim 4. By fitting a pair of halved mandrels into the through hole on the large end side of the connecting rod in which the large end and the small end are integrally formed, and driving a wedge between the pair of mandrels, A method for monitoring a rupture state when ruptured at left and right rupture portions from a rupture promoting portion provided on the left and right sides of the through hole in advance to the shaft portion side and the cap portion side of the large end portion of the connecting rod,
A first step of detecting strain generated at the time of breakage by a pair of left and right strain detection means provided on a holding means for holding the cap portion side on both the left and right sides at the time of breakage;
A second step of determining a rupture state based on detection signals respectively output from the pair of left and right strain detection means at the time of rupture,
A method for monitoring a broken state of a connecting rod, wherein in the second step, the quality of the broken state of the left and right broken portions of the connecting rod is determined based on a difference in strain detected by the pair of left and right strain detecting means. The pair of left and right strain detection means in the first step includes a pair of left and right strain detection means provided on at least one of the pair of mandrels,
A method for monitoring a broken state of the connecting rod according to claim 6. The breakage promoting portion is a V-shaped cutout for breakage,
In the second step , the method further includes a step of giving a warning when it is determined that the processing state of the V-shaped notch for fracture is defective.
A method for monitoring a broken state of the connecting rod according to claim 6. In the second step, when the difference between the left and right strains respectively output from the pair of left and right strain detecting means is greater than a predetermined value continuously n times or more (n is an integer of 1 or more), the connecting rod is provided. A step of determining that the V-shaped notch formed is defective in shape;
9. A method for monitoring a broken state of a connecting rod according to claim 8. In the second step, when it is determined that the V-shaped notch has a defective shape, a step of instructing automatic tool change to a V-shaped notch processing device provided with an automatic tool changing mechanism, In addition,
A method for monitoring a breaking state of a connecting rod according to claim 9.

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